Researchers at Shanghai University create tri-layered artificial blood vessels for the first time
By combining micro-imprinting and electro-spinning techniques, researchers at Shanghai University’s Rapid Manufacturing Engineering Center have developed a vascular graft composed of three layers for the first time. This tri-layered composite has allowed researchers to utilize separate materials that respectively possess mechanical strength and promote new cell growth - a significant problem for existing vascular grafts that have only consisted of a single or double layer.
Vascular grafts are surgically attached to an obstructed or otherwise unhealthy blood vessel to permanently redirect blood flow, such as in coronary bypass surgery. Traditional grafts work by repurposing existing vessels from the patient’s own body or from a suitable donor. However, these sources are often insufficient for a patient’s needs because of the limited supply in a patient’s body, and may be afflicted by the same underlying conditions that necessitate the graft in the first place. Accordingly, there has been a great deal of research towards developing synthetic vessels that can mimic natural ones, allowing new cells to grow around them and then degrade away, thereby creating new vessels.
"The composite vascular grafts could be better candidates for blood vessel repair," said Yuanyuan Liu, an associate professor at the Rapid Manufacturing Engineering Center. Liu’s team had previously worked with bone scaffolds, which are used to repair bone defects, before turning their attention to cardiovascular disease, and thus vascular grafts. They describe their current research in the journal AIP Advances, from AIP Publishing.
As a rule, surrogate scaffolds need to mimic the natural vasculature of their targeted tissue as much as possible. For blood vessel surrogates, this structural mimicry can be fabricated by electrospinning, a process which uses an electrical charge to draw liquid inputs – here a mixture of chitosan and polyvinyl alcohol – into incredibly fine fibers. Electrospinning also allows for a high surface-to-volume ratio of nanofibers, providing ample space for host cells to grow and connect. These components all naturally degrade within six months to a year, leaving behind a new, intact blood vessel.
The resulting structure, however, isn’t very rigid – the fly in the ointment for many previous models. To compensate for this, the researchers designed a three-layer model, in which the mixture was electrospun onto both sides of a microimprinted middle layer of poly-p-dioxanone, a biodegradable polymer commonly used in biomedical applications. The ends of this sheet were then folded and attached to make a tube-like vessel.
Liu and her team then seeded the scaffold with rat fibroblast cells, which are ideal candidates because of their ease of cultivation and quick growth rate, to test the scaffold’s efficacy in promoting cellular expansion and integration. The researchers found that the cells on these composite scaffolds proliferated quickly, likely due to the functional amino and hydroxyl groups introduced by the chitosan.
While a good deal of work remains before the prospect of human trials, Liu and her group are optimistic about the future of their research. Their next project is to test the implants in an animal model, to observe the structure’s efficacy with live vascular cells.
The article, "Composite Vascular Repair Grafts via Micro-imprinting and Electrospinning” is authored by Yuanyuan Liu, Ke Xiang, Haiping Chen, Yu Li and Qingxi Hu. It will appear in the journal AIP Advances on February 3, 2015 (DOI: 10.1063/1.4906571). After that date, it can be accessed at: http://scitation.aip.org/content/aip/journal/adva/5/4/10.1063/1.4906571
ABOUT THE JOURNAL
AIP Advances is a fully open access, online-only, peer-reviewed journal. It covers all areas of applied physical sciences. With its advanced web 2.0 functionality, the journal puts relevant content and discussion tools in the hands of the community to shape the direction of the physical sciences.
Jason Socrates Bardi
Jason Socrates Bardi | newswise
From ancient fossils to future cars
21.10.2016 | University of California - Riverside
Study explains strength gap between graphene, carbon fiber
20.10.2016 | Rice University
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
25.10.2016 | Earth Sciences
25.10.2016 | Power and Electrical Engineering
25.10.2016 | Process Engineering